Induction coil



Patented Sept. 6, 19 27.

UNITED STATES PATENT OFFICE.

STANISLAS Z. CHYLINSKI, OF NEW YORK, N. 'Y. ASSIGNOB TO WESTERN ELECTRIC v COMPANY, INCOBPORATEDQOF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

INDUCTION COIL.

Application filed December 18, 1923. Serial No. 681,358.

The object of this invention is to provide a simply and easily manufactured coil which has practically no stray magnetic field. In

accordance with this invention, a coil is built in which the winding is completely surrounded by core material that part of the core surrounding the wi'ndinghaving a much lower reluctance than that part lying inside. i

. The invention can be clearly understood by reference to the following detailed description in connection with the drawing, in

which, Fig.- 1 shows a perspective'view of one form of the invention,

Flg. 2,as1de view of one of the inner core pieces and,

Fig. 3, an end view'of the same core piece,

and

Fig. 4, a method of mounting the coils.

Referring to Fig. 1 in which is shown a coil embodying this invention which comprises an inner core made up of two pieces 4 and 5 which go together to form aspool on which is wound a winding 6 provided with terminals 8 and 9. The outer core piece or casing comprises a cover of silicon steel 15, the ends 16-and 17 of which are turned back to form grooves in which is placed a wire 11. The ends of the wire are twisted together to tightly clamp the casing and so 40 close the. air gap between it and thespool,

thus forming a closed magnet path. The

cover is further provided with lugs 10 which are bent over to prevent any lateral movement.

Figs. 2 and 3 show one of the inner spools 4 which are molded of iron dust core material such as that described in the patent to J. B. Speed, No. 1,274,952, granted August 6, 1918. The winding is wound in the groove.

0 14, two like'sections going together to form the spool. The grooves 13 of the two sections form a hole which may be used to receive a, mounting bolt. The spool is made in two sections for convenience in molding. It

i could be divided'in the opposite direction butsections of the shape shown were chosen so as to ehnnnate the air gap in the magnetic circuit.

Spools made in this manner have a relatively low permeability while the cover is made of material of relatively high permeability. In this way the magnetic material is so distributed that the reluctance of the path lying outside the winding is smaller than that lying inside' This tends to make the ratio of consumption of magnetic potential v along the path of the' flux proportional to the rateof generation. In this manner all parts on the surface of the coil adjacent its periphery are kept at practically'the same magnetic potential and there is substantially no tendency for the existence of flux external to the coil. 7

In addition, the cover, the ends of which are connected together by the binding wire,"

serves as an electric screenwhichtends to might cause cross-talk.

I have further found that by staggering these coils in mounting, I can practically preclude any possibility of inductive interference. This method of mounting is shown in Fig. 4, in which two coils 18and 19 are mounted on opposite sides ofv a mounting board 20 and securedthereto by means of mounting bolts 21 and 22. When the coils are staggered in this way, I find that I can mount them with the left hand edge of one in the same straight line as the right hand. edge of the other and have practically no interlinkage of magnetic flux.

eliminate any stray electric fields which It is understood that this invention is not meability than said first magnetic materialfl ion.

all points on the surface of said second section being at substantially the same magnetic potential.

2. An inductance coil comprising a spool of magnetic material, a winding wound on said spool and a cover of a different magnetic material from thatof said spool surrounding said winding and cooperating with said spool to form a substantially closed magnetic circuit, the reluctance of said cover being low in comparison with the reluctance of said spool whereby the consumption of magnetic potential in said magnetic circuit is substantially proportional to its rate of generation.

3. An inductance coil comprising a spool of molded iron dust core material, a winding' wound on said spool and acover of magnetic material of high permeability substantially completely enclosing said winding, said spool and said cover cooperating to form a substantially closed magnetic, path.

4. An inductance coil having a substantially closed magnetic circuit comprising a 5 core piece composed of molded iron dust core material, a second core-piece composed of molded iron dust core material forming with said first core piece a portion of said magnetic circuit without introducing-an air gapin the path of magnetic flux, a winding wound on said core pieces and a cover composed of magnetic material of high per- .meability surrounding said winding and cooperatingwith said core magnetic circuit,

5. An inductance coil comprising a semicylindricalcore piece composed of molded iron dust core material, a second semi-cylindrical core piece composed of molded iron dust core material, a winding wound on said core pieces and a third core piece composed of magnetic material of high permeability surrounding said Winding and cooperating with said'first andsecond mentioned core pieces to form a substantially closed magnetic circuit.

6. An inductance coil having a core'piece composed of magnetic material of low permeability, a winding wound on said core piece, and a second core piece composed of magnetic material of high permeability surrounding said winding, L and means for mounting said coil with said core piece of high permeability material adjacent to a similar core iece of a similar coil the axes of said coils being parallel and lying in the pieces to form said same plane, whereby substantially no interlinkage of magnetic flux takes place between said coils.

7. In combination, a mounting board, an inductance coil mounted on one side of said board, said coil comprising an inner core piece of iron dust core material, a winding wound on said core piece and a cover composed of magnetic material of high permeability surrounding said winding and cooperating with said inner core piece to form a substantially closed magnetic circuit, and a second similar inductance coil mounted on the opposite side of said mounting board and staggered with respect to said first mentioned coil whereby, there is substantially no interlinkage of magnetic flux between said coils.

8. A magnetic device, comprising a spoolshapedmember of magnetic material having flanges extending outwardly on all sides thereof, a winding between the flanges of said member, and a band of magnetic material extending between the edges of said flanges, and forming with said spool shaped member a practically complete enclosure for said winding.

9. A magnetic device comprising a spoolshaped member of magnetic material having flanges extending outwardly on all sides thereof, a winding between the flanges of said member, a band of magnetic material extending between the edges of said flanges and practically completely surrounding said winding with magnetic material and means for clamping said band against said edges.

10. In combination, an inductance coil comprising a spool of magnetic material,

a winding on said spool and a cover of magnetic material surrounding said winding and cooperating with said spool to form a substantially closed magnetic circuit, the reluctance of said cover being low in comparison with the reluctance of said spool and a second similar inductance coil mounted with its axis in the same plane and parallel to the axis of said first coil, said coils lying in diagonal quadrants of a rectangular system of coordinates, whereby there is substantially no interlinkage of magnetic flux between said coils.

In witness whereof, I hereunto subscribe my name this 14th day of December A. D., 1923.

STANISLAS z. CHYLINSKI. 

